Monday, February 27, 2012

Dry Eye In Dogs KCS

DRY EYE IN DOGS

Dry eye, also known as Keratoconjunctivitis Sicca (KCS), is a relatively common condition of the cornea and conjunctiva caused by a deficiency in tear production. It is rare in cats. It is most common in smaller breed dogs including Westies, Lhasas, Pugs, Shih tzus, Yorkies, Pekes and American Cocker Spaniels.

Usually what owners notice is excessive sticky mucous production in one or both eyes, especially after the pet has been sleeping. A dog will often wake up with thick green mucous dried around the eye (see image below).

The sclera (white portion of the eye) may be red and irritated as well as the conjunctiva. In chronic cases brown pigmentation may start to cover the cornea, vessels may grow into the cornea or corneal ulcers may develop.

The most common cause is an immune mediated adenitis. It can also be a congenital condition where the lacrimal glands (tear ducts) are hypoplastic or aplastic (virtually non-existent). It can sometimes be caused by certain medications, infections or metabolic disorders.

It is usually diagnosed based on clinical signs and a simple test called a Schirmer Tear Test where a small piece of paper is held in the eye for one minute (image 2) and the tear production is measured in millimeters. A normal dog has 15mm or more of tears; early or subclinical dogs have 11-14 mm, mild to moderate cases have 6-10 mm and severe cases have 5mm or less.

Treatment in most cases is life-long. It usually consists of using at minimum a tear substitute in the eye(s) such as Artificial Tears™ drops or ointments or some human over the counter products such as Genteal™ or Refresh™ drops. These need to be used several times each day. Other medications include lacrimostimulants, or medications that are supposed to help the eye start to produce more tears of its own. These include cyclosporine-A emulsions or tacrolimus drops. These medications usually have to be compounded at a pharmacy and used once or twice daily.